Method of and apparatus for drying compressed gases



W WILKINSON. METHOD OF AND APPARATUS FOR DRYING COMPRESSED GASES.

APPLICATION FILED OCT. 15. 1920.

1,376,985. Patented May 3, 1921.

' naw/M306 01172: 35 #41 Guam I $2.44 (9mm 34M144 UNITED STATES PATENT OFFICE.

WALTER wrnxmson, or JERSEY CITY, New mnsmr, lemma m Am B A Y, A conronn'non on NEW Yo EDI-anon mnrnon or AND arrina'rus FOR mums comrnnssnn eases,

Application filed October 15, 1920. Serial No.417,250.

To all whom it may concern:

Be it known that I, WALTER WI KINsoN, a citizen of the United States, residin I at Jersey City, in the county .of Hudson, tate of New Jersey, have invented certain new and useful Improvements in Methods of and Apparatus for Drying Compressed Gases; and I do hereby declare the following, to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to matically illustratesfone. form of apparatus adapted for use in carryingout the inven tion. It is to be understood that no attempt has been made to illustrate details of construction which may' be readily sup plied by those skilled in the art, and that various changes may, therefore, be made in the structure illustrated.

. Various gases are shipped in containers under pressure and in filling such containers the gas must be previously compressed. WVater lubricated compressors are frequently employed for this purpose particularly in the case of oxygen which cannot be ,compressed in the presence of ordinary lubricants because of the danger of combustion. When gases are compressed in water lubricated compressors they absorb large quantities ofmoisture which is carried along with the gas and separates therefrom in the containers or bottles. The result is that the bottles contain a considerable quantity of water which reduces their capacity and the gas delivered therefrom is always in a moist a condition and consequently unfit for various uses.

The purpose of the present invention is to avoid the difficulty arising in connection with the compression of gases 1n water lubricated compressors as herembefore ex- Specifleation of Letters Patent.

Patented-May 3, 1921.

plamed and particularly in the compression of oxygen derlved from the liquefaction and separation of the constituents of air.

In separating oxygen from air by liquefaction and rectification, the products, ox gen and vnltrogen, are delivered from t e apparatus at substantially atmos heric pressure and in a relatively cold condition. The cold is recovered by heat exchange between the outgoing gases and the air entering the system in accordance with well understood prlnclples The oxygen thus recovered at atmospherlc pressure and temperature is then sub ected to compression in a suitable water lubricated compressor and the compressed-gas is delivered through a manifold to the containers or bottles in which it is transported.

It is proposed to utilize a portion of the cold derived from the gases escaping from the liquefaction apparatus to separate the moisture from the gas as it leaves the compressor. This may be accomplished by caus- 1ng the compressed gas to travel in indirect contact with the cold gas from the liquefaction apparatus. The compressed gas is thereby cooled and a substantial portion of the moisture is removed at the low temperature prevailing. If the compressed gas is permitted, however, to travel in one directlon only through the exchanger, it will escape therefrom at a relatively low temperature and the cold will be dissipated. In accordance with the present invention this difliculty is met by returningthe cold compressed gas in indirect contact with further portions of compressed gas entering the exchanger so that the cold is transferred to the 1ncom1ng compressed gas and the moisture is thereby separated therefrom. If there was no leakage of heat into the apparatus, the only cold necessarily supplied would be that required to condense the moisture from the oxygen. It is necessary, however, due to heat leakage, to introduce more cold gas from the liquefaction apparatus and a certain proportion of this gas travels at all times through the exchanger.

In carrying out the invention'the apparatus illustrated in the drawing is preferably employed. Referring to the drawing, 5 in-' dicates a pipe adapted to convey a gas from a separation apparatus such as that employed in the liquefaction, and rectification of gaseous mixtures. The gas passing through the pipe 5 has given up its cold in a suitable exchanger of the usual type and is, therefore, substantially at atmospheric temperature. The pipe 5 delivers the gas to a gasometer 6 where it is stored until re-.

quired. A pipe 7 connects the gasometer with the inlet of a compressor 8 which may be of the water lubricated type and adapted to discharge the gas at a suitable pressure through a pipe 9 which maybe provided with a purge 9. I

The gas thus discharged from the compressor is saturated with water vapor and unless this water vapor is removed before the gas enters the bottles it will separate therein with the disadvantages hereinbefore referred to. To insure the separation of the major portion of the moisture anexchanger of temperature is provided conslstlng of two units 10 and 11 which are similar in construction and adapted to receive the warm gas alternately so that when moisture congeals therein it may be melted while the other unit is employed for the separation of moisture in a further quantity of gas.

Each of the units 10 and 11 comprises a shell inclosing a bundle of tubes 12 which are connected to separate heads 13 and 14 at opposite ends of the shell. A plurallt of baflies 15 are arranged within the she l to cause the gas to flow in an upwardly d1- rected sinuous path in contact with the tubes. 1

The pipe 9 is connected to a valve chamber 17 having a valve 16 therein which may be shifted to cause the gas to follow the path in which it first enters one or the other of the units 10 or 11 as desired. Assuming that the gas is to first enter the unit 10, it is delivered from the valve chamber 17 to a pipe 18 which conveys it to the lower end of the unit 10. Thence the compressed gas passes upwardly around the bafiles 15 and in contact with the tubes 12 until it escapes through a pipe 19 which returns it to the valve casing 16. *The as passes from the valve chamber 16 to a pipe 20 which delivers it to the bottom of the unit 11 through which it passes in the same manner as in the unit 10 and the gas escapes through a pipe 21. Pipes 22 and 23 are provided to permit reversal of the flow of gas through the units so that when the unit 11 becomes clogged with congealed moisture owing to the lower temperature prevailing therein, the Warm incoming compressed gas may be directed first into this unit where it serves to melt the ice.

From the pipes 21 or 23, the cold compressed gas with the moisture removed therefrom is delivered to a valve casing 24 in which a valve 25 is provided with the passage 26 adapted to register with the pipes 21 or 23 and pipes 26 or 27. The latter pipes are connected to the heads 13 so that the cold compressed gas returns through the tubes 12 to the opposite heads 13, giving up its cold to the incoming compressed gas and escaping through pipes 29 or 28 to a valve chamber 30 having a valve 31 therein which is provided with a passage 32 adapted to register with either of the p1pes 28 or 29 and with an outlet pipe The latter pipe is'connected to a manifold 34 having pigtails 35 whereby the bottles 36 are connected thereto.

As previously explained, except for the leakage of heat into the exchanger and the removal of the heat of vaporization of the molsture, the apparatus so far as it has been described, would maintain itself at any temperature which might have been obtained. ()wlng to the leakage of heat and to the molsture, however, it is necessary to supply additional cold and consequently a pipe 37 is provided to convey a cold gas from the liquefaction apparatus to a valve chamber 38 having a valve 39 therein which is provided with a passage 40 adapted to connect the pipe 37 with either of pipe 41 or 42. The pipes 41 and 42 are connected to heads 14 previously described and the cold gas is thus delivered to a set of tubes 12 within the exchangers. The cold gas is warmed by indirect contact with the compressed gas and is delivered from heads 14 at the opposite ends of the units of pipes 42 and 43, communicating with the valve casing 30. A valve 31 in the casing 30 is provided with a passage 44 which connects either of the pipes 42 or 43 .with a pipe 45 whereby the gas is delivered to the gasometer 6, or at some other point through a branch 45 controlled by a valve 46. A valve 47 is provided in the pipe 45 to divert the gas into the branch. The cold gas from the pipe 37 is delivered to either unit 10 or 11 depending on which is employed at the time for separating the moisture while the other is being thawed by the passage of warm compressed gas therethrough. Purge bottles 46 are connected to each of the units 10 and 11 to permit removal. of the moisture accumulating therein.

From the foregoing description it will be apparent that a method of separating moisture from gases and an apparatus adapted to the accomplishment of the purpose recited, is provided and that the'separation of moisture may accordingly be accompllshed in a'simple and effective manner and without waste of the cold employed for this purpose. This is an important element in the successful operation to accomplish the removal of moisture by cold which must be carefully conserved throughout the liquefaction operation toprevent waste of energy in this operation.

arious changes may be made in the method as hereinbefore described without departing from the invention or sacrificing any of the advantages thereof.

I claim:

1. A method of separating moisture from compressed gases preliminary to the storage of the gas in shipping receptacles which comprises, causing the gas to travel in indirect contact and countercurrent with preceding portions thereof whereby the compressed gas is cooled to a temperature insuring separation of the major portion of the moisture carried by the gas, withdrawing the separated moisture while the gas is at the low temperature, conveying in indirect contact with the compressed gas additional cooling medium to compensate for heat derived from the surrounding atmosphere and from condensation of the moisture, and conveying the compressed dehydrated gas to the shipping receptacle.

2. A method of separating moisture from compressed gases preliminary to the storage of the gas in shipping receptacles which comprises, causing the gas to travel in indirect contact and countercurrent with preceding portions thereof whereby the compressed gas is cooled to a temperature insuring separation of the major portion of the moisture carried by the gas, withdrawing the separated moisture while the gas is at the low temperature, conveying cold products of the liquefaction of a gaseous mixture from which the gas is derived in indirect contact with the compressed gas to compensate for heat derived from the surrounding atmos phere and from condensation of the moisture'and conveying the compressed dehydrated gas to the shipping receptacle.

3. In an apparatus for separating moisture from compressed gas preliminary to the storage of the gas'in shipping receptacles which comprises an exchanger having means for conveying the gas in indirect contact and countercurrent with preceding portions thereof whereby the compressed gas is cooled to a temperature insuring separation of the major portion of the moisture carried by the gas, means permitting withdrawal of the separated moisture while the gas is at the low temperature, means for conveying additional cooling medium to the exchanger to compensate for heat derived from the surrounding atmosphere and from condensation of moisture and means for'conveying the compressed dehydrated gas to the shipping receptacles.

In testimony whereof I afiix my signature.

WALTER WILKINSON. 

